The disclosure relates to a pixel circuit and a display unit.
In the technical field of display units that display an image, a display unit utilizing an electric current-driven optical device as a light-emitting device of a pixel has been commercialized in recent years. Such an optical device includes an organic electroluminescence (EL) device, for example. The current-driven optical device has emission luminance which varies depending on a value of a flowing current. The organic EL device is a self-light-emitting device, and thus differs from a device such as a liquid crystal device. The display unit utilizing the organic EL device (organic EL display unit) therefore does not need a light source (backlight), thus is more lightweight, thinner, and higher in luminance than a liquid crystal display unit that needs a light source. Further, the organic EL device has a very high response speed of about several micro seconds, thus preventing the occurrence of an afterimage during display of a motion picture. Hence, the organic EL display unit is expected to be a mainstream next-generation flat panel display.
An active-matrix organic EL display unit has a configuration in which each scanning line is sequentially scanned, and a signal voltage corresponding to an image signal is sampled and is written into a storage capacitor. In other words, the line sequential scanning allows for the writing operation of the signal voltage. Further, in the organic EL display unit in which a threshold voltage and mobility of a driving transistor differ for each pixel, the organic EL device may possibly have irregular luminance, impairing uniformity of a screen when. Therefore, the active-matrix organic EL display unit performs correction operation that reduces the irregular luminance caused by the irregular threshold voltage and the irregular mobility of the driving transistor, in addition to the line sequential scanning. For example, reference is made to Japanese Unexamined Patent Application Publication Nos. 2006-133543 and 2006-030921.